I imagine the new HH will have some kind of Modem only mode akin to the Virgin Superhub.
Why would they bother?
Hopefully the third-party router market will quickly product equipment with VDSL modems built in, as they have for ADSL.
However it does leave the ISPs back in the bad-old-days of fault finding - the active Openreach NTE, meant there was a nice demarcation in the end users home. Now its always the CPE that is suspect. (just see the AAISP blogs).
James BT Infinity 2 19/09/2012 - Speeds 49 / 8.2 Mbps - Sync 53 / 9.5 Mbps @ 470m
Huawei modem -> RT-N66U -> Switch -> PC/Mac/Linux/NAS/Phone/TV - last speedtest
13 years of broadband - 1999 ntl:(512k/1M)/BTbusiness(2M)/Metronet(2M)/Bulldog(8M/16M)/BE(19M/16M)/BT FTTC(46M)